Abstract - The ability of the parasitic mite Varroa destructor to transmit Kashmir bee virus (KBV) to the Western honey bee (Apis mellifera) was investigated by exposing pupae from a KBV-negative colony to varying numbers of adult female mites from KBV-positive
colonies. After five days, the virus status of pupae and the mites was determined by RT-PCR. There was a significant relationship
between KBV-positive pupae and exposure to KBV-positive mites. No pupae were virus-positive when all the mites introduced
into a given cell subsequently tested negative. Mites testing positive for KBV transmitted virus about 70% of the time. The
percentage of KBV-positive V. destructor in a given cell also increased significantly, suggesting virus-free mites became virus-positive by cohabiting in the same
cell with virus-positive mites, and we calculated the mite-to-mite transmission rate as 51%. There was 100% sequence identity
of 415 bp KBV fragment amplified from bee pupae and mites, reflecting two isolates of the same virus source and supporting
the conclusion of virus transmission from mite to bee pupae.